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/js/model/ImprovedNoise.js

http://github.com/onedayitwillmake/RealtimeMultiplayerNodeJs
JavaScript | 68 lines | 45 code | 21 blank | 2 comment | 6 complexity | b5b6c1670be6076a16c871e4d5ccc887 MD5 | raw file
 1// http://mrl.nyu.edu/~perlin/noise/
 2(function () {
 3    var p = [151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10,
 4        23, 190, 6, 148, 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33, 88, 237, 149, 56, 87,
 5        174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122, 60, 211,
 6        133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54, 65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208,
 7        89, 18, 169, 200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64, 52, 217, 226, 250, 124, 123, 5,
 8        202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213, 119,
 9        248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9, 129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232,
10        178, 185, 112, 104, 218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249,
11        14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205,
12        93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180];
13
14    for (var i = 0; i < 256; i++) {
15
16        p[256 + i] = p[i];
17
18    }
19
20    function fade(t) {
21
22        return t * t * t * (t * (t * 6 - 15) + 10);
23
24    }
25
26    function lerp(t, a, b) {
27
28        return a + t * (b - a);
29
30    }
31
32    function grad(hash, x, y, z) {
33
34        var h = hash & 15;
35        var u = h < 8 ? x : y, v = h < 4 ? y : h == 12 || h == 14 ? x : z;
36        return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
37
38    }
39
40    // Retrieve the namespace
41    RealtimeMultiplayerGame.namespace("RealtimeMultiplayerGame.model");
42    RealtimeMultiplayerGame.model.noise = function (x, y, z) {
43
44        var floorX = ~~x, floorY = ~~y, floorZ = ~~z;
45
46        var X = floorX & 255, Y = floorY & 255, Z = floorZ & 255;
47
48        x -= floorX;
49        y -= floorY;
50        z -= floorZ;
51
52        var xMinus1 = x - 1, yMinus1 = y - 1, zMinus1 = z - 1;
53
54        var u = fade(x), v = fade(y), w = fade(z);
55
56        var A = p[X] + Y, AA = p[A] + Z, AB = p[A + 1] + Z, B = p[X + 1] + Y, BA = p[B] + Z, BB = p[B + 1] + Z;
57
58        return lerp(w, lerp(v, lerp(u, grad(p[AA], x, y, z),
59            grad(p[BA], xMinus1, y, z)),
60            lerp(u, grad(p[AB], x, yMinus1, z),
61                grad(p[BB], xMinus1, yMinus1, z))),
62            lerp(v, lerp(u, grad(p[AA + 1], x, y, zMinus1),
63                grad(p[BA + 1], xMinus1, y, z - 1)),
64                lerp(u, grad(p[AB + 1], x, yMinus1, zMinus1),
65                    grad(p[BB + 1], xMinus1, yMinus1, zMinus1))));
66
67    }
68})();